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Physical Sciences and Mathematics Commons

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Full-Text Articles in Physical Sciences and Mathematics

Non-Critical Waveguide Alignment For Vertically-Coupled Microring Using A Mode-Expanded Bus Architecture, Chyng Wen Tee, K. A. Williams, R. V. Penty, I. H. White Oct 2006

Non-Critical Waveguide Alignment For Vertically-Coupled Microring Using A Mode-Expanded Bus Architecture, Chyng Wen Tee, K. A. Williams, R. V. Penty, I. H. White

Research Collection Lee Kong Chian School Of Business

Vertically coupled microrings in an all-pass filter configuration are fabricated with a range of waveguide misalignments deliberately introduced into the lithography masks to demonstrate noncritical fabrication requirements. The microrings have a mode-expanded bus design which allows a greatly reduced variation in power coupling coefficient-only 6% for fabrication misalignments as high as 1 mum. This represents a five-fold improvement in fabrication tolerance when compared with conventional designs.


A Hybrid Scatter Search/Electromagnetism Meta-Heuristic For Project Scheduling, Dieter Debels, Bert De Reyck, Roel Leus, Mario Vanhoucke Mar 2006

A Hybrid Scatter Search/Electromagnetism Meta-Heuristic For Project Scheduling, Dieter Debels, Bert De Reyck, Roel Leus, Mario Vanhoucke

Research Collection Lee Kong Chian School Of Business

In the last few decades, several effective algorithms for solving the resource-constrained project scheduling problem have been proposed. However, the challenging nature of this problem, summarised in its strongly NP-hard status, restricts the effectiveness of exact optimisation to relatively small instances. In this paper, we present a new meta-heuristic for this problem, able to provide near-optimal heuristic solutions for relatively large instances. The procedure combines elements from scatter search, a generic population-based evolutionary search method, and from a recently introduced heuristic method for the optimisation of unconstrained continuous functions based on an analogy with electromagnetism theory. We present computational …


Monolithic Integration Of Collimating Fresnel Lens For Beam Quality Enhancement In Tapered High Power Laser Diode, F. K. Lau, Chyng Wen Tee, X. Zhao, K. A. Williams, R. V. Penty, I. H. White, M. Calligaro, M. Lecomte, O. Parillaud, N. Michel, M. Krakowski Jan 2006

Monolithic Integration Of Collimating Fresnel Lens For Beam Quality Enhancement In Tapered High Power Laser Diode, F. K. Lau, Chyng Wen Tee, X. Zhao, K. A. Williams, R. V. Penty, I. H. White, M. Calligaro, M. Lecomte, O. Parillaud, N. Michel, M. Krakowski

Research Collection Lee Kong Chian School Of Business

We demonstrate, for the first time, a monolithic integrated lens for wide aperture gain-guided tapered laser beam quality enhancement by compensating the quadratic phase curvature. The 3mm long tapered laser with an output aperture of 170μm adopted in this design consists of a gain-guided tapered section and an index-guided ridge section and operated at 980nm. The lens design is implemented by focus ion beam etching (FIBE) technique, whereby the laser diode is mounted p-side up in order to facilitate the etching process. The lens is located 600μm away from the junction of the tapered and ridge sections, and is 40μm …